This book constitutes revised selected papers of the 19th International Conference on Applications of Declarative Programming and Knowledge Management, INAP 2011, and the 25th Workshop on Logic Programming, WLP 2011, held in Vienna, Austria, in September 2011. The 19 papers presented in this volume were carefully reviewed and selected from 27 papers presented at the conference and initially a total of 35 submissions. The book also contains the papers of two invited talks. The papers are organized in topical sections on languages; answer-set programming and abductive reasoning; constraints and logic programming; answer-set programming and model expansion; application papers; and system descriptions.